/*
 * Copyright (c) 2006-2007 Erin Catto http://www.gphysics.com
 *
 * This software is provided 'as-is', without any express or implied
 * warranty.  In no event will the authors be held liable for any damages
 * arising from the use of this software.
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 * 1. The origin of this software must not be misrepresented; you must not
 * claim that you wrote the original software. If you use this software
 * in a product, an acknowledgment in the product documentation would be
 * appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 * misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 */

package org.box2dflash.dynamics.joints {
	import org.box2dflash.common.math.*;
	import org.box2dflash.dynamics.joints.*;
	import org.box2dflash.dynamics.*;
	import org.box2dflash.common.Internal;
	use namespace Internal;

	/// Distance joint definition. This requires defining an
	/// anchor point on both bodies and the non-zero length of the
	/// distance joint. The definition uses local anchor points
	/// so that the initial configuration can violate the constraint
	/// slightly. This helps when saving and loading a game.
	/// @warning Do not use a zero or short length.
	
	public class DistanceJointDef extends JointDef {
		public function DistanceJointDef() {
			type = Joint.e_distanceJoint;
			//localAnchor1.Set(0.0, 0.0);
			//localAnchor2.Set(0.0, 0.0);
			length = 1.0;
			frequencyHz = 0.0;
			dampingRatio = 0.0;
		}

		/// Initialize the bodies, anchors, and length using the world
		/// anchors.
		public function initialize(b1:Body, b2:Body,
								anchor1:Vec2, anchor2:Vec2):void {
			body1 = b1;
			body2 = b2;
			localAnchor1.v(body1.localPoint(anchor1));
			localAnchor2.v(body2.localPoint(anchor2));
			var dX:Number = anchor2.x - anchor1.x;
			var dY:Number = anchor2.y - anchor1.y;
			length = Math.sqrt(dX * dX + dY * dY);
			frequencyHz = 0.0;
			dampingRatio = 0.0;
		}

		/// The local anchor point relative to body1's origin.
		public var localAnchor1:Vec2 = new Vec2();
		/// The local anchor point relative to body2's origin.
		public var localAnchor2:Vec2 = new Vec2();
		/// The equilibrium length between the anchor points.
		public var length:Number;
		/// The response speed.
		public var frequencyHz:Number;
		/// The damping ratio. 0 = no damping, 1 = critical damping.
		public var dampingRatio:Number;
	}
}	
